Reviewer name and names of any other individual's who aided in reviewer	Istvan Nagy
Do you understand and agree to our policy of having open and named reviews, and having your review included with the published papers. (If no, please inform the editor that you cannot review this manuscript.)	Yes
Is the language of sufficient quality?	Yes
Please add additional comments on language quality to clarify if needed
Are all data available and do they match the descriptions in the paper?	No
Additional Comments	Minor revision in the manuscript body is suggested. Gene annotation and repeat annotation data need some minor revision) See details in the "Additional Comments" section.
Are the data and metadata consistent with relevant minimum information or reporting standards? See GigaDB checklists for examples <a href="http://gigadb.org/site/guide" target="_blank">http://gigadb.org/site/guide</a>	Yes
Additional Comments
Is the data acquisition clear, complete and methodologically sound?	Yes
Additional Comments
Is there sufficient detail in the methods and data-processing steps to allow reproduction?	Yes
Additional Comments
Is there sufficient data validation and statistical analyses of data quality?	Yes
Additional Comments
Is the validation suitable for this type of data?	Yes
Additional Comments
Is there sufficient information for others to reuse this dataset or integrate it with other data?	Yes
Additional Comments	The submitted dataset reports and improved chromosome-level assembly and annotation of the doubled-haploid line Kyuss of Lolium perenne. The present v2.0 assembly is showing significant improvements as compared to the Kyuss v1.0 assembly published by the same group in 2021: The new assembly incorporates 99% of the estimated genome size in seven pseudo-chromosomes and the >99% BUSCO completeness of the gene space is also impressive. Below are mine remarks and suggestions to the present version of manuscript: Genome assembly and polishing It's indicated that for the primary assembly of the present work the same source of ONT reads were used as for the previous Kyuss v1.0 assembly. However, in the present manuscript the authors report clearly better assembly quality as opposed to the Kyuss v1.0 assembly. The question remains open, whether the authors achieved better results by changing/optimizing the primary assembly parameters, and/or applying a step-wise, iterating strategy with repeated rounds of long-read and short-read corrections? By any means, a more detailed description/specification of assembly parameters would be desirable. Genome annotation In the provided annotation file "kyuss_v2.gff" in the majority of cases gene IDs consisting of the reference chromosome ID and of an ongoing number, like "KYUSg_chr1.188" are used. However in a few cases gene IDs like "KYUSt_contig_1275.207" are also used. This inconsistency might create confusions for future users of Kyuss_2 resources, and while the later type of gene IDs might be useful for internal usage, they became meaningless, as instead of contigs now pseudo-chromosomes (and some unplaced scaffolds) are used as references. The authors should modified the gff files and use a consistent naming scheme for all genes. Further, transcript DNA sequences as well as transcript protein sequences with consistent naming schemes should also be provided. Repeat annotation The authors should modify Table 3 by specifying and breaking down repeat categories according to the Unified Classification System of transposable elements, by giving Order and Superfamily specifications (like LTR/Gipsy and LTR/Copia etc, in accord with the provided gff file "kyuss_v2_repeatmask.gff"). According to the provided repeat annotation BED file, more than 750K repeat features have been annotated on the Kyuss_2 genome. Of these repeat features 57815 are overlapping with gene features and 25843 of these overlaps are longer than 100 bp. This indicate that a substantial portion of the 38765 annotated genes might represent sequences coding for transposon proteins and/or transposon related ORFs. I suggest that the authors revise the gene annotation data (and at least remove gene annotation entries that show ~100% overlap with repeat features). Assembly quality assessment "The quality score(QV) estimated by Polca for Kyuss v2.0 was 50, suggesting a 99.999% base-level accuracy with the probability of one sequencing error per 100 kb. The estimated accuracy of Kyuss v1.0 is 99.990% (QV40, Table 1), which is 10 times lower than Kyuss v2.0, suggesting that Kyuss v2 is more accurate than Kyuss v1.0." In my opinion, this sentence needs clarification as readers might have difficulties to properly interpret this - especially considering the facts that the same long-read data was used for both for the v1 as well a for the v2 assembly versions, the short-read mapping rate was the same (99.55%) for both versions and the K-mer completeness analysis results differed only slightly (99,39% vs. 99.48%).
Any Additional Overall Comments to the Author	The submitted dataset reports and improved chromosome-level assembly and annotation of the doubled-haploid line Kyuss of Lolium perenne. The present v2.0 assembly is showing significant improvements as compared to the Kyuss v1.0 assembly published by the same group in 2021: The new assembly incorporates 99% of the estimated genome size in seven pseudo-chromosomes and the >99% BUSCO completeness of the gene space is also impressive. Below are mine remarks and suggestions to the present version of manuscript: Genome assembly and polishing It's indicated that for the primary assembly of the present work the same source of ONT reads were used as for the previous Kyuss v1.0 assembly. However, in the present manuscript the authors report clearly better assembly quality as opposed to the Kyuss v1.0 assembly. The question remains open, whether the authors achieved better results by changing/optimizing the primary assembly parameters, and/or applying a step-wise, iterating strategy with repeated rounds of long-read and short-read corrections? By any means, a more detailed description/specification of assembly parameters would be desirable. Genome annotation In the provided annotation file "kyuss_v2.gff" in the majority of cases gene IDs consisting of the reference chromosome ID and of an ongoing number, like "KYUSg_chr1.188" are used. However in a few cases gene IDs like "KYUSt_contig_1275.207" are also used. This inconsistency might create confusions for future users of Kyuss_2 resources, and while the later type of gene IDs might be useful for internal usage, they became meaningless, as instead of contigs now pseudo-chromosomes (and some unplaced scaffolds) are used as references. The authors should modified the gff files and use a consistent naming scheme for all genes. Further, transcript DNA sequences as well as transcript protein sequences with consistent naming schemes should also be provided. Repeat annotation The authors should modify Table 3 by specifying and breaking down repeat categories according to the Unified Classification System of transposable elements, by giving Order and Superfamily specifications (like LTR/Gipsy and LTR/Copia etc, in accord with the provided gff file "kyuss_v2_repeatmask.gff"). According to the provided repeat annotation BED file, more than 750K repeat features have been annotated on the Kyuss_2 genome. Of these repeat features 57815 are overlapping with gene features and 25843 of these overlaps are longer than 100 bp. This indicate that a substantial portion of the 38765 annotated genes might represent sequences coding for transposon proteins and/or transposon related ORFs. I suggest that the authors revise the gene annotation data (and at least remove gene annotation entries that show ~100% overlap with repeat features). Assembly quality assessment "The quality score(QV) estimated by Polca for Kyuss v2.0 was 50, suggesting a 99.999% base-level accuracy with the probability of one sequencing error per 100 kb. The estimated accuracy of Kyuss v1.0 is 99.990% (QV40, Table 1), which is 10 times lower than Kyuss v2.0, suggesting that Kyuss v2 is more accurate than Kyuss v1.0." In my opinion, this sentence needs clarification as readers might have difficulties to properly interpret this - especially considering the facts that the same long-read data was used for both for the v1 as well a for the v2 assembly versions, the short-read mapping rate was the same (99.55%) for both versions and the K-mer completeness analysis results differed only slightly (99,39% vs. 99.48%).
Recommendation	Minor Revision